[Android] Add gn support for multidex.

build/config/android/internal_rules.gni

Index: build/config/android/internal_rules.gni
diff --git a/build/config/android/internal_rules.gni b/build/config/android/internal_rules.gni
index 9895c460102fa50a4095bd405efe364986a8d9e1..17a1335e83b756da4993b17cc01f5a9f99d61b19 100644
--- a/build/config/android/internal_rules.gni
+++ b/build/config/android/internal_rules.gni
@@ -223,6 +223,63 @@ template("java_binary_script") {
 template("dex") {
   set_sources_assignment_filter([])
 
+  _multidex = defined(invoker.multidex) && invoker.multidex

[agrieve, 2015/11/16 19:02:33]

nit: It would be more GN'y to call this "enable_multidex" or "use_multidex"

[jbudorick, 2015/11/16 20:45:56]

I'm still getting a handle on what's GN'y. switched to enable_multidex

+
+  if (_multidex) {
+    _main_dex_list_path = invoker.output + ".main_dex_list"
+    template("main_dex_list_helper") {

[agrieve, 2015/11/16 19:02:33]

doesn't look like this is used more than once, so no need to use a template...
Unless you're planning on re-using it, in which case it's fine.

[jbudorick, 2015/11/16 20:45:56]

I'm not. I think I patterned this off of something else, but I forget what.
Removed the template.

+      action(target_name) {
+        forward_variables_from(invoker,
+                               [
+                                 "deps",
+                                 "inputs",
+                                 "sources",
+                                 "testonly",
+                               ])
+
+        script = "//build/android/gyp/main_dex_list.py"
+        depfile = "$target_gen_dir/$target_name.d"
+
+        main_dex_rules = "//build/android/main_dex_classes.flags"
+
+        outputs = [
+          depfile,
+          invoker.output,
+        ]
+
+        args = [
+          "--depfile",
+          rebase_path(depfile, root_build_dir),
+          "--android-sdk-tools",
+          rebased_android_sdk_build_tools,
+          "--main-dex-list-path",
+          rebase_path(invoker.output, root_build_dir),
+          "--main-dex-rules-path",
+          rebase_path(main_dex_rules, root_build_dir),
+        ]
+
+        if (defined(invoker.args)) {
+          args += invoker.args
+        }
+
+        if (defined(invoker.sources)) {
+          args += rebase_path(invoker.sources, root_build_dir)
+        }
+      }
+    }
+
+    _main_dex_list_target_name = "${target_name}__main_dex_list"
+    main_dex_list_helper(_main_dex_list_target_name) {
+      forward_variables_from(invoker,
+                             [
+                               "args",
+                               "sources",
+                             ])
+      output = _main_dex_list_path
+      deps = invoker.deps
+    }
+  }
+
   assert(defined(invoker.output))
   action(target_name) {
     forward_variables_from(invoker,
@@ -258,6 +315,16 @@ template("dex") {
       args += [ "--no-locals=1" ]
     }
 
+    if (defined(invoker.multidex) && invoker.multidex) {
+      args += [
+        "--multi-dex",
+        "--main-dex-list-path",
+        rebase_path(_main_dex_list_path, root_build_dir),
+      ]
+      deps += [ ":${_main_dex_list_target_name}" ]
+      inputs += [ _main_dex_list_path ]
+    }
+
     if (defined(invoker.args)) {
       args += invoker.args
     }